Lighter, more rigid, more compact: Porsche has produced its first complete housing for an electric drive using 3D printing. The engine-gearbox unit produced using the additive laser fusion process passed all the quality and stress tests without any problems. “This proves that additive manufacturing with all its advantages is also suitable for larger and highly-stressed components in electric sports cars”, says Falk Heilfort, Project Manager in the Powertrain Advanced Development department at the Porsche Development Centre in Weissach.
The additively manufactured alloy housing is more lightweight than a conventionally casting part and reduces the overall weight by approximately ten per cent. Thanks to special structures that have only become
possible due to 3D printing, the stiffness in highly stressed areas has nevertheless been doubled. The honeycomb structure reduces the oscillations of the thin housing walls and thus considerably improves the acoustics of the drive as a whole. Another advantage is that thanks to additive manufacturing several functions and parts can be integrated into one monolithic part. This considerably reduces assembly work and directly benefits part quality.
Optimization of the electric drive started with the design integration of components such as bearings, heat exchangers and oil supply. This was followed by the computer-calculated definition of loads and interfaces and the optimization of loading paths by integrating the lattice structures.
The weight of the housing parts was reduced by approximately 40% due to the integration of functions and optimisation of the topology. This represents a weight savings of around 10% for the entire drive due to the lightweight construction. Despite a wall thickness of only 1,5 millimetres, the stiffness between the electric motor and the gearbox was increased by 100% due to the lattice structures. The honeycomb structure reduces the oscillations of the thin housing walls and thus considerably improves the acoustics of the drive as a whole. The integration of parts made the drive unit more compact, significantly improved the drive package, and reduced the assembly work by around 40 work steps. This is equivalent to a reduction in the production time of approximately 20 minutes. An additional benefit: integration of the gearbox heat exchanger with optimised heat transmission improves the cooling of the drive as a whole.
The housing produced using the 3D printing process shows the potential of additive manufacturing for Porsche when it comes to product innovation and new business areas such as customisation with new offers for customers and spare parts. This manufacturing technology is technically and economically interesting for Porsche, specifically for special and small series and motorsports.